A rapid spectrophotometric method for the determination of esterase activity

Area of Science:

• Biochemistry
• Enzymology
• Spectrophotometry

Background:

• Esterase activity is crucial in biological processes.
• Existing spectrophotometric assays often require color extraction, complicating measurements.
• A direct, continuous monitoring method for esterase activity is needed.

Purpose of the Study:

• To develop a novel spectrophotometric assay for continuous esterase activity monitoring.
• To enable quantitative determination of esterase units in solution.
• To facilitate esterase staining detection in gel electrophoresis.

Main Methods:

• Developed a spectrophotometric assay measuring absorbance changes at 510 nm.
• Utilized alpha-naphthyl ester substrates hydrolyzed to alpha-naphthol.
• Coupled alpha-naphthol with Fast Blue RR salt to form a diazo dye complex.
• Directly monitored the formation of the diazo dye complex without extraction.

Main Results:

• The assay continuously records esterase activity by monitoring absorbance changes.
• Direct monitoring of diazo dye complex formation was achieved.
• The method demonstrated utility for quantitative esterase unit determination.
• Esterase staining activity detection on gel electrophoresis was successful.
• The assay was limited to alpha-naphthyl ester substrates due to non-linear absorbance changes with beta-naphthyl esters.

Conclusions:

• A novel, direct spectrophotometric assay for esterase activity has been developed.
• This method allows for continuous monitoring and quantitative analysis of esterase activity.
• The assay is applicable to both solution-based quantification and gel electrophoresis detection of esterases.